Will bad crankshaft sensor cause no spark?
A bad Crankshaft Position sensor is a common cause of no starts. The signal from this sensor goes to the PCM or ignition module that switches the ignition coil(s) on and off. In ignition systems with a single coil and distributor, a bad coil or a cracked distributor cap or rotor can prevent the spark plugs from firing.
How does the crank sensor control the ignition module?
The ignition module starts to turn On and Off the ignition coils in their proper firing order to create spark, after the crank signal arrives. This On/Off action is the Switching signal referred to above. Under 400 RPM’s, the ignition control module controls spark timing without the help of the fuel injection computer.
What is the crank sensor on a GM 3.1L engine?
This article will help you test the ignition control module (ICM) and 3X crankshaft position sensor on all of the GM 3.1L and 3.4L overhead valve engines (the 3X crank sensor is also known as the 7X Crank Sensor).
What happens when the ignition coil is activated?
Now, when the ignition coil is activated to spark, it feeds spark to two engine cylinders at the exact same time. So then, in a nutshell, when you turn the key to crank and start the car, this is what happens: The engine starts to crank, inducing the crankshaft position sensor to start producing its crank signal.
What kind of signal does the ignition module need?
OK, moving on along… for the ignition module to create this Switching signal, it needs to receive a C ran k shaft P osition (CKP) sensor signal (this signal is usually referred to as the Triggering signal and in GM service literature it’s known as the 3X or 7X CKP signal).
The ignition module starts to turn On and Off the ignition coils in their proper firing order to create spark, after the crank signal arrives. This On/Off action is the Switching signal referred to above. Under 400 RPM’s, the ignition control module controls spark timing without the help of the fuel injection computer.
Where is the CKP sensor on the ignition module?
As you can see, the CKP sensor signal is critical for the ECM and ignition control module to start sparking the Igntion coils at START UP and at all engine speeds. The CKP sensor is located on the block.
What is the 7x reference signal on the ignition module?
The ignition control module upon receiving this AC Volts crank signal, converts it into a DC digital signal and sends it to the ECM. This digital signal is called the 7X REFERENCE signal. The ECM, upon receiving this 7X REFERENCE signal, returns to the ignition module an Ignition Coil Control signal thru’ two different circuits.
Can a bad ICM cause a crank sensor to go bad?
Therefore, the second symptom that leads you on the path of a BAD ICM or crank sensor is: No spark at any of the ignition coils. Of course, when it comes to Ignition System failures, this is not an absolute truth. These two components could display any number of behaviors when they go bad.